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Cumulative Trauma Disorders

Preventive Strategies

Barbara Lutz, RDH, AAS, BS

Cumulative Trauma Disorders (CTDs) are the leading
work-related injuries currently reported by professionals.1 Due to
the nature of the profession, dentists present many risk factors for these
disorders (eg, repetitive wrist and hand motion, awkward body postures,
positioning for extended periods). These factors may result in malposition,
strain, and misalignment of the musculoskeletal system, which compromises
nerves, joints, and muscles. In addition, musculoskeletal disorders of the
upper extremities affect the neck, shoulder, elbow, hand, wrist, and fingers,
which may lead to injuries to the tendons, muscles, and nerves.2
These disorders limit daily activities and may curtail a dentist’s career.

Cumulative Trauma Disorders are not caused by accidents or
job-related environmental risks; rather, they develop over time.3
The US government has defined CTDs as any musculoskeletal pain associated with
activities performed at work.4 Cumulative Trauma Disorder is not a
medical diagnosis, but rather a label for pain perception. The
term cumulative trauma disorder identifies a large group of conditions that
result from traumatizing the body in either a minute or major way over a period
of time. It is the build up of trauma which causes the disorder. As other repetitive motions of daily life can
affect an individual, controversy has emerged over the role of occupational influences
in the etiology of CTDs.1

Causes and
Considerations

The literature suggests that nerve response to injury causes
structural change to connective tissues within that nerve.5 When
pressure on an area becomes constant, vascular obstruction causes the nerves to
become hypoxic.6 Motor skills may become impaired at the onset; this
condition is, however, reversible. Without treatment, permanent damage may
result, as keeping the nerve dilated causes edema and further pressure on the
nerve. In addition, nerve fibers may be destroyed, leading to muscle atrophy,
weakness, or loss of function. While it is true that there is no connective
tissue in nerves per se, the structure of the nerve is supported by neuro
filaments. The nerves can be injured by direct compression to the nerve, or by
compressing the blood vessels supplying the nerves (vasa nervosa). This can
result in nerve edema and swelling. With significant nerve damage the muscles
loose inervation then begin to atrophy and fibrose. When muscles remain in a
low-level exertion state from non-movement, they experience decreased blood
flow. In rare cases, or in cases where there is occlusion or laceration of a
blood vessel, this reduction in blood supply may lead to fibrosis of the
muscles and result in permanent scarring.

The neck and back regions are especially susceptible to
muscle strain. Extensive muscle contraction is needed to hold the head out of
its neutral position; this strain puts undue stress on the spinal disks, resulting
in pinched nerves and herniated disks.5 Certain predisposed medical
conditions can also increase the risk of developing CTDs (eg, diabetes,
rheumatoid arthritis, hypo- or hyperthyroid disease).5

Preventive Strategies

All members of the dental team are at risk of experiencing
CTD-like pain at work. Dentists, in particular, report significant neck,
shoulder, and lower back pain (Figure 1).6 The dentist must be aware
of detrimental habits that may add to his or her risk for developing CTDs. This
includes being cognizant of poor body mechanics and the need to recondition
himself/herself to correct posture (Table 2)7. Dentists should take
breaks between patients and perform stretch exercises to reduce muscle tension.
Schedules should also be arranged to avoid consecutive heavy patient cases.

Table 2.7

Preventive Strategies

Working Position

Avoid
prolonged extensions (bending) or deviations (twisting) of the wrist

Maintain
neutral sitting position

Keep
head and shoulders relatively relaxed and straight

Keep
back straight and elbows close to sides

Distribute
body weight evenly on operator’s chair when sitting; avoid leaning to one
side or the other

Avoid
working in one position for prolonged periods of time

Schedule

Allow
brief (5-10) minute breaks in the daily work schedule for relaxation,
rest, and stretching exercises

Avoid
scheduling consecutive heavy of intense patient cases

Since the work environment has a profound effect on physical
health, it is essential for the dentist to address how his or her surroundings
may influence his or her body mechanics. It is important to keep supplies handy
and the room temperature comfortable, as well as to maintain adequate room
lighting. Instruments must be sharpened to decrease repetitive motion and
forceful exertion during instrumentation. The addition of loupes or bifocal
protective eyewear can further enhance body mechanics and assist the user in
the maintenance of a neutral position. Even with excellent eyesight, dentists can miss much detail without magnification and by wearing surgical loupes not only benefits from such enhancement but prevents straining of the neck and upper/lower back.

In order to prevent the development of a CTD, the following
criteria should be applied, whenever possible, to the clinician’s working
position8:

Head
upright;

Chin
slightly tucked in;

Feet
flat on the floor;

Shoulders
relaxed and level;

Ears
positioned over the shoulders;

Weight
centered on the stool; and

Elbows
near sides

Conclusion

The development of CTDs may severely compromise the
practitioner’s ability to properly execute his or her day-to-day functions. Dentists
must, therefore, be conscious of the symptoms associated with these disorders,
and seek treatment at the onset; diagnosis & treatment are key to
effectively managing CTDs. Once the dentist has been made aware of the
anatomical implications of a CTD, he or she may begin taking steps to prevent
and correct its occurrence in the operatory.

Centers
for Disease Control and Prevention. National Institute of Occupational Safety
and Health. Ergonomics and musculoskeletal disorders. Available at: http://www.cdc.gov/niosh/topics/ergonomics/.
Accessed July 1, 2008.